Ball type valve

ABSTRACT

BALL TYPE VALVE PARTICULARLY SUITED FOR USE AS AN ANGLE COCK IN RAILWAY AIR BRAKE SYSTEMS. THE VALVE IS CHARACTERIZED IN THAT THE SPHERICAL HEAD: (A) IS THE DEFORMABLE VALVING ELEMENT SUBJECT TO WEAR AND CAN BE REPLACED EASILY WITHOUT USING SPECIAL TOOLS OR REQUIRING REMOVAL OF THE VALVE FROM THE LINE, (B) IS UNIFORMLY COMPRESSED AROUND THE ZONE OF CONTACT WITH THE SEAT IN THE CLOSED POSITION, (C) MAY BE BALANCED WITH RESPECT TO THE PRESSURES AT BOTH SIDES OF THE SEAT, AND (D) TRANSLATES ALONG ITS OWN CENTERLINE AND PIVOTS ABOUT AN AXIS ECCENTRIC TO THE CENTER OF THE SEAT SO THAT IT ROTATES ON THE SEAT FOR AN INITIAL PHASE OF ITS OPENING MOVEMENT AND SEPARATES FROM THE SEAT DURING THE FINAL PHASE OF SUCH MOVEMENT.

March .23, 1971 .T. H. ENGLE 5 3 am; TYPE VALVE Filed Oct. 16, 1969 2Sheets-Sheet 1 FIG! INVENTOR THOMAS H. ENGLE BY X ATTORNEYS March 23,1971 T. H. ENGLE 3,512,310

BALL TYPE VALVE Filed Oct. 16, 1969 ,2 Sheets-Sheet 2 E": I l3 u 12o. l8l9 4 7 J I I 23 I I4 i 13a FIGS THOMAS H. ENGLE INVENTOR ATTORNEYSUnited States Patent Oflice 3,5723% Patented Mar. 23, 1971 US. Cl.137-315 8 Claims ABSTRACT OF THE DISCLOSURE Ball type valve particularlysuited for use as an angle cock in railway air brake systems. The valveis characterized in that the spherical head:

(a) is the deformable valving element subject to wear and can bereplaced easily without using special tools or requiring removal of thevalve from the line;

'(b) is uniformly compressed around the zone of contact with the seat inthe closed position;

() may be balanced with respect to the pressures at both sides of theseat; and

(d) translates along its own centerline and pivots about an axiseccentric to the center of the seat so that it rotates on the seat foran initial phase of its opening movement and separates from the seatduring the final phase of such movement.

BACKGROUND AND SUMMARY OF THE INVENTION There is a need in the railroadindustry for a reliable ball type angle cock of competitive price whichcan be operated by a relatively small torque, affords good flowmetering, and allows easy replacement of the wearing valving elementwithout removing the valve from the brake pipe or requiring specialtools. The object of this invention is to provide a ball type valvewhich satisfies this need.

According to the preferred form of the invention, the deformable,wearing element of the valve is the spherical head which is mounted on apivoting carrier which can be withdrawn from the valve body along thestem axis after removal of a stem bonnet. The head, which can slidealong its centerline relatively to the carrier, is balanced with respectto pressure and is spring biased into engagement with a rigid,nonwearing seat. As the valve opens, the head swings clear of the seat,so the risk of entrapment of foreign particles between the head and seatis minimized. Moreover, the deformable element is compressed uniformlyaround the circumference of the zone of contact with the seat in theclosed position, and this, of course, tends to increase sealingreliability under low temperature condition. The pivot axis of thecarrier is eccentric to the center of the seat in two perpendiculardirections, and outward translation of the head under the action of thebiasing spring is limited. The arrangement is such that the head slidesacross, or rotates on, the seat, and thus affords good flow graduation,for only an initial portion of its opening movement, and thereafter thehead lifts off the seat. This scheme permits use of the spring todevelop the head-seat contact pressure without risk of permitting acorner of the seat to gouge the head during its closing movement.

BRIEF DESCRIPTION OF THE DRAWINGS The preferred embodiment of theinvention is described herein in detail with reference to theaccompanying drawings in which:

FIG. 1 is an axial sectional view of the improved angle cock with thehead in closed position and the handle rotated 90 into the plane ofsection.

FIG. 2 is an enlarged sectional view taken on line 22 of FIG. 1, butshowing the head in open position.

FIG. 3 is an exaggerated schematic diagram showing the effect of thevalve geometry.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in FIGS. 1 and 2, thenew angle cock in cludes a cast body 11 containing a through flowpassage 12, a rigid, nonwearing annular seat 13 which is pressed intothe body and encircles passage 12, and a deformable head 14 which ismounted on a pivoting carrier 15. Seat 13 preferably is made ofstainless steel and has either a conical or a spherical valving surface13a. However, surface 13a may be a convex surface of revolution formed,for example, by rounding the left end of seat 13. Head 14 is made ofeither rubber or glass-filled Teflon and is provided with a valvingsurface 14a in the form of a zone of a sphere which has a centerlinethat lies in a common plane with the centerline of surface 13a. Ifsurface 13a is spherical, the radii of the two valving surfaces areequal. On the other hand, if surface 13a is conical or convex, theradius of surface 14a is selected so that this surface is tangent tosurface 13a at its medial diameter.

Head 14 is formed with a cylindrical bore 16 which is coaxial wihsurface 14a and which receives a piston 17 fixed to carrier 15. Pistonl7 and cylinder 16 guide head 14 for translatory motion along thecenterline of surface 14a. The head is biased in the outward directionalong this centerline by a pair of coil compression springs 18 and 19,and its motion in this direction is limited by a stop screw 21 which isthreaded into piston 17 and is coaxial with surface 14a. Piston 17 andcylinder 16 also define a motor space 22 within head 14 which is sealedfrom the portion 12a of passage 12 to the left of seat 13 by an O-ring23, but is connected with the opposite portion 12b of the flow passagethrough the annular clearance space 24 between the head and stop screw21. The diameter of piston 17 is equal to the medial diameter of valvingsurface 13a, and therefore it should be evident that head 14 issubstantially balanced with respect to the pressures in passage portions12a and 12b. As a result, head-seat contact pressure depends only uponthe force developed by springs 18 and 19 and can be relatively low.This, of course means that only a small torque will be required to openand close the valve.

The head carrier 15 is formed at one end into a stem 15a which projectsfrom body 11 and to which is afiixed a conventional angle cock handleassembly 25. Carrier 15 also is provided with a pair of trunnions 15band 150 which journal it in bonnet 26 and body 11, respectively, forrotation about a pivot axis 27 which is normal to the common planecontaining the centerlines of valving surfaces 13a and 14a. Stops (notillustrated) define the open and closed positions of the valve. socarrier 15 has a range of motion of The bonnet 26 is held in body 11 bya snap ring 28 which bears against an annular shoulder 29 formed on itsouter periphery and is seated in a groove formed in body 11. Shoulder 29is spaced inward from the end face 26a of bonnet 26 a distance greaterthan one-half the diameter of the wire from which ring 28 is made, andthe outer periphery of the bonnet between the shoulder and end face 26ais shaped to prevent snap ring 28 from moving out of the body groove.This arrangement insures that bonnet 26 will not be ejected from body 11by the pressure in passage portion 12a which acts upon its inner endface 26b. Bonnet 26 is urged upward, as viewed in FIG. 1, against snapring 28 by a coil compression spring 31, so the bonnet can be moveddownward to uncover, and thereby permit installation or removal of, snapring 28. The body bore which re- 3 ceives bonnet 26 is large enough toaccommodate the assembly comprising carrier 15 and valve head 14;therefore, replacement of the valve head can be accomplished easilywithout removing the valve body from the line or using special tools.

The lower end of biasing spring 31 is seated on a snap ring fitted in agroove in carrier 15, and thus serves the additional purpose of urgingthe carrier into abutment with the body shoulder 32. Therefore, if thevalve is so manufactured that the vertical distance between shoulder 32and the centerline of seat 13 is matched closely to the correspondingdistance between the lower end of carrier 15 and the centerline of head14, spring 31 will insure that the two centerlines remain in the sameplane during service. The lower end of carrier 15 is in continuouscommunication with the atmosphere through a filtered vent port :33, andthe diameters of the trunnions 15b and 150 are equal. Therefore, carrier15 is balanced with respect to pressure in the direction of the pivotaxis 27, and, as a result, spring 31 need exert only a moderate biasingforce.

As those skilled in the art are well aware, the emergency portion of anautomatic air brake system responds to a prescribed rate of decrease ofbrake pipe pressure. Therefore, when the angle cock at the end of atrain is opened to charge the brake pipe sections of newly added cars,an unintended emergency brake application can be produced throughout thetrain if the valve does not afford reasonably good flow metering. In thecase of a conventional ball type valve, this flow-graduating actionnormally is provided by causing the head to pivot about an axis thatpasses through the center of the seat so that the head will slide acrossthe seat. However, this approach cannot be used in the new valve becausehere headseat contact pressure is developed by a spring, andconsequently the head must be able to translate along its centerline,and the head must be spaced from the seat in the fully open position ofthe valve in order to minimize restriction to flow through passage 12and to preclude entrapment of foreign particles between the matingvalving surfaces 13a and 14a. If head 14 pivoted about an axis whichpasses through the center of surface 13a, biasing springs 18 and 19would shift it outward along piston 17 as soon as the head was movedbeyond the margin of the seat. As a result, the corner 13b of the seatwould gouge the edge region 14b of the head 14 each time the valve wasclosed. In accordance with the teachings of the invention, this problemis eliminated, without impairing the ability of the valve to afford goodfiow-metering action, by the combination of stop 21 and a properlocation for pivot axis 27.

Referring to the schematic diagram of FIG. 3, the pivot axis 27 ofcarrier 15 is offset longitudinally from the center SC of valvingsurface 13a in the direction of seat 13, and also is offset laterallyfrom center SC in the direction away from head 14 when the latter is inthe fully open position H-l. (It should be understood that the center SCof a non-spherical surface 13a is the center of an imaginary spherewhich is tangent to the surface and has a radius equal to the radius ofhead surface 14a.) In a typical case, the longitudinal and lateraleccentricities X and Y are about 0.043 and 0.096 inch, respectively.Preferably, the centerlines SCL and HCL of the two valving surfaces 13aand 14a, respectively, coincide when the valve is fully closed, andtherefore axis 27 is spaced from the head centerline HCL a distanceequal to the lateral eccentricity Y.

When the head 14 is moved from the fully open position H-l toward theclosed position H-4, its centerline HCL remains tangent to an imaginarycircle 34 centered at axis 27 and having a radius equal to the lateraleccentricity Y, and initially its center HC moves in a circular are 35which also is centered on axis 27 and has a radius determined by stop21. In the illustrated example, it is assumed that stop 21 is so setthat are 35 intersects seat centerline SCL at the center SC of the seat,but settings giving arcs of slightly greater or smaller radii can beused. As the head swings to the H-2 position, its valving surface 14a isgradually brought into abutment with seat surface 13a. Since, in the H-2position, the center HC2 of head surface 14a coincides with the centerSC of the seat surfaces 13a, the two surfaces now will be perfectlyaligned and will be in contact with each other throughout a zone ofcontact of considerable angular extent. The location of the H-2 positiondepends upon the ratio of the lateral eccentricity Y to the longitudinaleccentricity X and usually lies between about 50 and 60 away [from theopen position H-l. In any case, since the leading edge 14b of the headis well within the margin of the seat by the time the head reaches thisposition of initial contact H-2, it will be evident that the edge cannotbe gouged by seat corner 13b.

As head 14 moves from the H-2 position to the fully closed H-4 position,seat 13 forces it to move inward against the opposing bias of springs 18and 19, so the center of surface 14a ceases to move along circular are35. During this phase of the closing movement, the centerline HCL ofhead surface 14a first moves away from seat center SC and then, as thehead approaches the H4 position, it moves into coincidence with seatcenterline SCL and again passes through the seat center. The positionH-3 of maximum misalignment is midway be tween the two positions H-2 andH4 wherein the seat and head centers coincide. If the parts of the valvewere perfectly rigid, and head 14 could not cock even slightly on guidepiston 17, the head could lift off seat 13 as shown by the dashed lineposition H-3 in FIG. 3 and open a narrow gap of considerable angularextent between the mating surfaces 13a and 14a. In practice, however,the head 14 is deformable, and it can cock on its guide. Therefore,since the maximum spacing or misalignment 2 between head centerlineHCL-3 and seat center SC is on the order of only 0.005 to 0.010 inch,the surfaces 13a and 14a will remain in contact. In effect, thetranslatory and rotary motions of head 14 cause it to rotate about theseat center SC. Thus, surface 14a merely slides across or rotates onseat surface 13a as the head moves between the H-2 and H4 positions.

During opening movement of the valve, head surface 14a tends initiallyto rotate about the center SC of seat surface 13a, so it slides acrossthe seat surface and gradually opens the flow path through passage 12.The combined effects of this area-graduating action and the low torquelevel afforded by the use of a pressure balanced head allows theoperator to meter flow through the valve well enough to control the rateat which the pressures in passage portions 12a and 12b equalize. As aresult, inadvertent emergency brake applications can be avoided. Whenthe head reaches the H-2 position, the flow area of the valve will haveincreased to the limit of the range in which useful flow metering can beaccomplished. Therefore, at or about this position, head 14 engages stop21. The stop precludes further outward translation of the head along itscenterline, so, as carrier 15 continues to pivot toward fully openposition, head 14 commences to rotate about axis 27. As a result,valving surface 14a is lifted away from seating surface 13a.

Since the valving surfaces 13a and 14a are permitted to slide acrosseach other through only the limited range of motion required foreffective flow metering, the new design minimizes the risk that foreignparticles caught between the valving surfaces will score one or theother in a manner that produces a leakage path across the seatingsurface 13a when the valve is closed. It also will be observed that,when head 14 is in closed position H-4, it is compressed uniformlyaround the entire 360 of the head-seat contact zone (i.e., all radiifrom center SC to surface 13:: pass through equal thicknesses of headmaterial). This arrangement tends to increase the reliability of theseal between the head and seat, particuularly under low temperatureoperating conditions.

Although the flow metering action afforded by the new valve satisfiesthe requirements for angle cocks used in railway brake systems, itshould be evident that the valve will afford more precise meteringaction if head edge 14b is provided with a small V-notch or meteringslot analogous to those employed in hydraulic valves of the slidingspool type.

It should also be noted that, while the head 14 in the preferred valveis balanced with respect to the pressures in passage portions 12a and12b, the basic design can be modified to afford a controlled amount ofunbalance in situations where the direction of flow does not change. Forexample, if the fluid always flows from left to right in FIG. 1, thehead-seat contact force can be made to vary with the pressure in passageportion 12a by merely reducing the diameter of piston 17 relatively tothe medial diameter of seat surface 13a.

I claim:

1. A ball type valve comprising (a) a body (11) containing a flowpassage (12) encircled by a seat (13) having an annular valving surface(13a);

(b) a carrier (15) mounted in the body for rotation about a pivot axis(27) which lies in a plane which is normal to the centerline (SCL) ofthe valving surface (13a) of the seat and is positioned between thatsurface and its center (SC);

(c) a deformable head (14) which is mounted to rotate with the carrierand has a valving surface (14a) in the form of a zone of a sphere,

(d) the centerlines (HCL and SCL) of the two valving surfaces lying in acommon plane and being spaced equal distances (Y) from the pivot axis(27);

(e) means (16, 17) guiding the head (14) for sliding movement relativelyto the carrier along the centerline (HCL) of its valving surface (14a);

(f) spring means (18, 19) biasing the head outward along said guidingmeans; and

(g) stop means (21) limiting outward movement of the head under theaction of said biasing means,

(h) whereby the opening movement of the head (14) consists of an initialphase in which it rotates essentially about the center (SC) of the seatand its valving surface (14a) slides across the valving surface (13a) ofthe seat, and a final phase in which it rotates about the pivot axis(27) and its valving surface separates from the seat.

2. A valve as defined in claim 1 in which the guide means comprisescooperating piston and cylinder elements (17, 16) which are coaxial withsaid valving surfaces (13a, 14a), one of said elements being fixed tothe carrier (15 and the other being fixed to the head (14).

3. A valve as defined in claim 2 in which the head (14) is balanced withrespect to the pressures in portions (12a, 12b) of said flow passage(12) at opposite sides of the seat when the valve is closed.

4. A valve as defined in claim 3 in which (a) said piston (17) andcylinder (16) define a closed space (22) within the head whichcommunicates with said flow passage at one side (12b) of the seat; and

(b) the diameter of said cylinder is equal to the median diameter of thevalving surface (13a) of the seat. 5. A valve as defined in claim 1 inwhich, in the closed position of the valve, the centerlines (HCL, SCL)and centers (HC, SC) of the two valving surfaces (13a, 14a) coincide.

6. A valve as defined in claim 1 wherein (a) the carrier (15) isprovided with a stern (15a) which projects from the body (11) and with apair of trunnions (150, 1512) which journal it for rotation in the bodyand in a removable bonnet (26) which closes an opening in the body; and(b) said opening in the body is large enough to pass the assemblyincluding the carrier (15) and the head (14).

7. A valve as defined in claim *6 wherein (a) the carrier (15) isbalanced with respect to the pressure in the body in the direction ofsaid pivot axis (27); Y

(b) the bonnet (26) is free to slide in said body opening and is held inplace by a snap ring (28) which is seated in the body and is adapted tobear against a portion (29) on the outer periphery of the bonnet; and

(c) a spring (31) reacting between the bonnet (26) and the carrier (15)urges the bonnet outward against the snap ring (28) and urges thecarrier inward into end abutment with a wall (32) in the body.

8. A valve as defined in claim 7 wherein the snap ring (28) is confinedby the bonnet (26) and the body (511) when said bonnet portion (29) isin abutment with it, but is exposed sufiiciently to permit removal whenthe bonnet is forced inward against the opposition of said spring (31).

References Cited UNITED STATES PATENTS 3,033,513 5/1962 Vulliez 251--1633,254,872 6/1966 Roos 251-163 3,301,271 1/1967 Burke 137-315 HAROLD W.WEAKLEY, Primary Examiner US. Cl. X.R. 251163, 283

